#使用datatime库进行日期类的相关操作
# 用法 1：
# import datetime
# data1 = datetime.datetime(2005,12,22)
# # data1 = datatime.datatime(year=2005,month=12,day=22)
# data2 = datetime.datetime.now()
# print(data2 - data1)

# 用法 2：(简化)
# from datetime import datetime
# # data1 = datetime(year = 2005,month = 12,day = 22)
# data1 = datetime(2005,12,22)
# data2 = datetime.today()
# print(data2 - data1)

# 用法 3：(as 相当于 typedef)
# import datetime as dt
# data1 = dt.datetime(2005, 12, 22)
# data2 = dt.datetime.today()
# print(data2 - data1)